Hydraulic fluid delayed action toggle switch actuator



Dec. 16, 1969 F, D. MAHONEY HYDRAULIC FLUID DELAYED ACTION TOGGLE SWITCH ACTUATOR Filed April 21, 1967 I I I9 INVENTOR. FRANK n. MAHONEY W W ATWRNEYS United States Patent 3,484,090 HYDRAULIC FLUID DELAYED ACTION TOGGLE SWITCH ACTUATOR Frank D. Mahoney, 68 Mulberry Lane, Atherton, Calif. 94025 Filed Apr. 21, 1967, Ser. No. 632,594 Int. Cl. G04b 1/00; F16f 13/00; F03g N04 US. Cl. 2671 9 Claims ABSTRACT OF THE DISCLOSURE An improved time delay actuator for use in combination with a mechanically actuated switch. The actuator comprises a mounted dash pot having a slidably engaging plunger with its rate of movement controlled by the flow of fluid in a sealed fluid circuit. The fluid circuit is isolated or sealed interior of the dash pot by a membrane sealed at one end to the top of the dash pot and attached at the bottom end to the piston of the plunger. This piston slideably engages the dash pot walls and in cooperation with these walls establishes the boundary between top and botton fluid reservoirs interior of the sealed fluid circuit. A timer orifice extending through the piston establishes controlled fluid communication between the top and bottom reservoirs. Typically, the elastic membrane has a memory holding the piston at a static or normal position interior of the dash pot. When the plunger is rammed or forced to a position removed from this normal or static position, the memory of the elastic membrane will urge the piston, to return at a rate which is proportional to theflow of fluid through the timer orifice between the reservoirs thereby actuating the accessible operating member of the switch in a timed sequence.

This disclosure relates to an improved time delay actuator for use in combination with a switch having an accessible operating member which responds to mechanical force by making, breaking or changing the connections interior of the switch mechanism. Actuators of the class disclosed typically comprise plungers which advance, retract or otherwise move relative to a dash pot or cylinder at a rate of movement controlled by fluid or frictional damping. The advancing plunger is positioned with respect to the switch so as to throw or alternately position the accessible operating member during its controlled advance.

Such dash pot or cylinder and piston actuators have heretofore been unable to efficiently accommodate their damping fluid in a perfectly sealed circuit. The absence of such a sealed circuit has the disadvantage of permitting the damping fluid such as hydraulic oil and the like, to leak or otherwise discharge. Further, foreign particles and impurities, such as dirt, dust, grease and the like, frequently enter into and interfere with the damping mechanism so as to alter appreciably the time period of the actuator.

An object of this invention is to provide a time delay cylinder and piston actuator having a perfectly sealed hydraulic circuit arresting this undesired leakage of damping fluid and preventing such particles and impurities from interfering with the rate of actuator movement. According to this aspect of this invention, a tubular membrane is installed interior of a dampening piston and cylinder defining the boundaries of a fluid circuit. The tubular membrane is sealed at one end to the top of the cylinder and fastened at the other end to the piston. The piston slideably engages the walls interior of the cylinder and delimits in such engagement the boundary between first and second fluid reservoirs bounded by the 3,484,090 Patented Dec. 16, 1969 cylinder, piston and tubular membrane. A timer orifice through the piston interconnects these reservoirs permitting the piston to move relative to the cylinder at a rate which is proportional to the volume of damping fluid flowing through the timer orifice.

A further object of this invention is to provide a flexible fluid circuit seal which is capable of supplying actuating force or movement to a damping piston or plunger. Accordingly, a flexible and elastic membrane interconnects a plunger and dash pot in a sealed relationship providing a fluid damping ambient interior of the dash pot. The memory of the connected elastic membrane urges the piston or plunger to a normal or static position interior of the dash pot or cylinder. When the piston or plunger is moved with an actuating force to oppose the memory of the elastic membrane, the membrane elastically deforms simultaneously accommodating the movement of the piston or plunger and the changing reservoir boundaries for the fluid circuit. Upon release of the actuating force, the memory of the membrane supplies the actuating forces for return of the piston or plunger to its normal or static position thereby supplying the mechanical force for the disclosed actuator.

The construction provides a closed fluid operating system wherein the elastic membrane that permits changing of the boundaries of the fluid circuit can also provide an elastic memory to control movement of the piston or plunger. Additionally, the system is silent. Therefore, it can be utilized as a timer for a detonation device and because of its silent operation it can not be detected.

Other objects, features and advantages of the present invention will be more apparent after referring to the following specifications and attached drawing in which:

FIG. 1 is a side elevational cross section of the actuator according to this disclosure shown mounted adjacent a switch and with the piston removed from normal or static position;

FIG. 2 is an elevational view of the actuator and switch showing the damping cylinder or piston in partial cross section with the plunger or piston in the static or normal position;

FIG. 3 is a top elevational view of the damping cylinder or dash pot taken along section 3-3 of FIG. 2 illustrating specifically an adjustable mounting for the actuator; and

FIG. 4 is a side elevational view of an alternate em bodiment of the actuator mounting.

Referring to the drawing and with particular reference to FIGS. 1 and 2, a switch mechanism A is shown having a mounting B to which dash pot C is attached so as to permit protruding plunger D to pass in actuating relationship to the switch.

Switchmechanism A is shown having a plate 14 aflixed to bulkhead 16 having operating member 17 protruding therefrom. Switch A is typically an electrical mechanism for making, breaking or changing the flow of electrical current interiorly thereof.

Mounting B positions the illustrated actuator relative to switch mechanism A so that plunger D can pass accessible operating member 17 in an actuating relationship. The mounting is shown in FIGS. 2 and 3 as a protruding elongate U-shaped clamp 19 attached at either end to plate 14 dimensioned to accommodate a mating C-shaped bayonet protrusion 20 from plunger D in a laterally slidable manner. The actuatoris installed by bringing bayonet protrusion 20 immediately over clamp 19 and moving the bayonet into slideable engagement therewith. As is apparent, the U-shaped clamp and C-shaped bayonet protrusion can be dimensioned for frictional mating engagement in a vertical direction so as to insure firm attachment of the mounted actuator at a selected position laterally of the clamp 19 as described in greater detail with reference to FIG. 3 below.

Dash pot C comprises elongate cylinder 22 having closed bottom 24 and an open top 25 with walls 26 therebetween. Typically walls 26 are parallel and cylindrical with respect to the axis of dash pot C. As is apparent, cylinder walls 26 may be of a configuration which is other than cylindrical. Configured in elongate cylinder 22 adjacent open top 25 there is provided a continuous and peripheral seal seat 28. Seat 28 is here illustrated as a J-shaped groove which faces upwardly in the direction of the opening of cylinder 22. Cylinder cap 30 covers open top 25 of cylinder 22 and has a downwardly depending cap flange 31 which fastens to the exterior of seat 28 along inwardly directed fastening bends 33. For purposes which will hereinafter become apparent there is configured a downwardly depending and peripheral annular seat flange 35 on the underside of cap 30 which is equidistance from seat 28 around the cylinder 22. Medially of cap 30 there is provided a rod aperture 37 illustrated specifically in FIG. 3 as square in cross section.

Plunger D is shown comprising piston 40 having elongate rod 42, square in cross section protruding therefrom with cam surface 43 at the opposite end thereof.

A tubular membrane 45 is shown aflixed to piston 40 at bottom end 46 and having sealing ring 47 at the opposite end thereof. As is apparent, the attachment of membrane 45 to piston 40 may be affected by any means suflicient to provide a continuous fluid seal isolating one side of the membrane from the other. As is illustrated in FIGS. 1 and 2, a convenient way of effecting such a seal is to cast or mold piston 40, attached membrane 45, and seal ring 47 as a unitary and continuous body. Such mouldings are commonly made of tubular, resilient plastic and the like, and by techniques well known to those skilled in the art. As is apparent, piston 40 and ring 47 may alternately be fabricated independently of membrane 45 and attached thereto in a sealed and fixed relationship by means well known to those skilled in the art.

Ring 47 is configured and dimensioned for forcible mating engagement interior of the seal seat 28 and typically includes a number of annular ridges 48 which establish successive seals for the fluid contained within the cylinder. When the ring 47 is mated with this seat, cylinder cap 30 is placed over open top 25 of cylinder 22 and snapped in place so that the bends 33 grip the exterior bottom annular edge of seat 28. The under surface of cap 30 immediately overlying groove 28 compresses seal 47 into a forced and sealed engagement interior of seat 28. Annular flange 35 in the under surface of cap 30 cooperates with seat 28 and ring 47 holding the membrane in firm sealing engagement interior of the sealing groove or ring.

Piston 40 slideably engages the walls 26 of cylinder 22 along a sealing flange 50. Sealing flange 50 is here illustrated as a tapered semiflexible unitary member of piston 40 depending angularly upward in the direction of open top 25 from the upper extremity of the piston and making an acute angle with the cylinder wall therebelow. As is apparent, flange 50 may alternately be fabricated independently of piston 40 and attached thereto.

A hydraulic fluid 51 such as silicone oil is contained in sealed circuit 52 which has rigid boundaries defined by cylinder 22 and flexible boundaries defined by piston 40 and membrane 45. The fluid circuit is divided into top reservoir 53 and bottom reservoir 54 by the contact of piston 40 will walls 26 along sealing flange 50'. Reservoirs 53 and 54 are interconnected by timer orifice 56 which extends through piston 40 establishing fluid communication between the two reservoirs. As is apparent, the rate of fluid flow between the reservoirs can be varied by changing the size of orifice 56 or varying the viscosity of the hydraulic fluid.

As hereinbefore mentioned, membrane 45 is commonly made of a tubular shaped, resilient rubber, plastic or the 4 like. This membrane may be varied in thickness and supplied with memory characteristics of varying intensity depending upon the thickness of the formed membrane. As is apparent, the memory character of the membrane can be utilized in both tension and compression depending upon the particular application desired for the actuator.

With particular reference to FIG. 2, the timer actuator of the present invention is illustrated with membrane 45 in the relaxed or normal memory position. As can be seen, top reservoir 53 is shown with a relatively small volume while bottom reservoir 54 contains the bulk of the hydraulic fluid 51.0f sealed circuit 52. An actuating force is applied to rod 42 typically at cam surface 43 forcing piston 40 in the downward direction of arrow 58. Fluid 51 interior of circuit 52 is forced from bottom reservoir 54 into top reservoir 53 as the piston travels the length of cylinder 22. As is apparent, fluid 51 will'travel through timer orifice 56 during this downward stroke as well as past sealing flange 50.

Sealing flange 50 performs a particularly useful function during the downward stroke of piston 40. In the usual application of the actuator, a rapid downward stroke of piston 40 is desired. If fluid 51 is solely restricted to flow through orifice 56, such a rapid stroke would not be possible. Accordingly, sealing flange 50 with its upwardly depending angular taper from the top portion of piston 40 permits such a rapid stroke by temporarily deforming inwardly from walls 26 of cylinder 22. This deformation permits fluid 51 to pass rapidly around the entire periphery of piston 40 from bottom reservoir 54 into top reservoir 53.

After application of the actuating force described with reference to FIG. 2, actuator will have the configuration specifically illustrated in FIG. 1. Bottom reservoir 53 will have a minimal volume while top reservoir 54 will contain the bulk of the hydraulic fluid 51. Membrane 45 will deform inwardly towards rod 42 so as to accommodate the bulk of the hydraulic fluid 51 interior of sealed circuit 52.

Upon the release of the actuating force on rod 42, the memory of membrane 45 will urge piston 40 upwardly, returning the piston to the relaxed or normal position illustrated in FIG. 2. Such urging will increase the pressure of the hydraulic or damping fluid 51 in top reservoir 53 urging sealing flange 50 into contact with cylinder walls 25. This excess fluid pressure on top reservoir 53 will force angular sealing flange 50 of piston 40 into frictional contact with cylinder walls 26, scaling for the most part the fluid flow around the periphery of piston 40. The fluid communication between reservoirs 53 and 54 will, thus, be restricted to the flow of fluid through timer orifice 56. The rate of movement of piston 40 and its depending rod 42 in the upward direction of arrow 59 shown in FIG. 1 will be proportional to the flow of fluid interior of the timer orifice. As is apparent, the upward movement of piston 40 will actuate operating member 17 of switch A by the upward movement of cam surface 43.

With reference to FIG. 3, the elongate U-shaped clamp 19 permits slideable engagement of the actuator relative to operating member 17. The actuator is shown in a position where cam surface 43 will contact operating member 17. In the event that contact between the actuator and operating member 17 is not desired, dash pot C can be slideably and frictionally moved laterally along elongate clamp 19 so as to move cam surface 43 out of contact with member 17.

FIG. 3 additionally illustrates the usefulness of rod aperture 37 in cylinder cap 30 and its cooperation with rod 42. Rod 42 has been illustrated as square in configuration with a cross section mating aperture 37. Rotation of the rod and cam surface 43 will be prevented during the movement of piston 40 by the engagement along its elongate square cross section of the mating periphery of aperture 37. As is apparent any cross section of rod 42 which is other than circular will arrest or control such rotation. Alternatively, a circular cross section could be used where rotation of the rod was desired to change the position of the cam surface 43.

FIG. 4 illustrates an alternate application of the timer actuator, and more specifically, an alternate mounting and switch application therefor. Switch A is actuated by the inward and outward movement of extending operating member 17 similar to switch mechanisms commonly associated with the electrical headlight circuit of automobiles. Mounting B comprises an elongate L-shaped member 63 having a magnet 64 affixed to one end and a U-shaped clamp 19 afiixed at the other extremity. Typically, bulkhead 16' will be constructed of a metal which responds to the attractive force of magnet 64 holding mounting member 63 firmly attached thereto. The actuator will be attached to the end of member 63 furthest removed from bulkhead 16' at U-shaped clamp 19 as hereinbefore described. When an actuating force is applied to cam surface 43, the actuator will advance operating member 17 so as to operate switch mechanism A in the time delay sequence already set forth. Thus, the timer actuator can be used as a time delay turn 01f of automobile lights to permit the driver to leave the automobile and still use the automobile headlights for the set amount of time.

If desired, a spring can be positioned between the bottom of the cylinder 22 and the piston 40 to aid return of the piston to static position.

Although the foregoing invention has been described in some detail .by way of illustration and example for the purposes of clarity and understanding, it is understood that certain changes and modifications may be practiced within the spirit of the invention as limited only by the appended claims.

What is claimed is:

1. A time delay cylinder and piston actuator having an internal sealed fluid circuit comprising: a damping cylinder having a closed bottom and an open top with walls therebetween for the confinement of fluid interiorly thereof; a piston slideably engaging the walls interior of the cylinder when moved in at least one direction and spring urged in said one direction; a tubular membrane defining the boundaries of said fluid circuit interior of the said damping cylinder and attached and sealed at one end to said cylinder and at the other end to said piston; said piston defining first and second reservoirs in said fluid circuit delimited by the engagement of said piston with said walls; a timer orifice through said piston interconnecting said first and second reservoirs whereby said piston is capable of movement interior of said cylinder at a rate proportional to the rate of fluid flow through said timer orifice between said reservoirs.

2. A time delay cylinder and piston actuator according to claim 1 and wherein: said tubular membrane is resilient and urges said piston in said one direction adjacent a first position along said cylinder; a rod contacting said piston and attached for slideable movement interior of said cylinder, said rod suitable for ramming said piston in a direction opposite to said one direction to a second position along said cylinder whereby the resilience of said membrane urges said piston from said second position to said first position.

3. A time delay cylinder and piston actuator according to claim 2 and wherein said rod contacting said piston includes: guide means con rolling the rotation of said rod as said rod moves with said piston.

4. A time delay cylinder and piston actuator according to claim 2 and wherein: said rod has a cam surface furthest removed from said piston; said rod has a constant cross section which is other than circular; a cylinder cap having an aperture slideably mating the constant cross section of said other than circular rod, whereby said rod does not rotate as said piston moves.

5. A time delay cylinder and piston actuator according to claim 1 and wherein: means for normally urging said piston adjacent one position interior of said cylinder are attached to said piston.

6. A time delay cylinder and piston actuator according to claim 1 and having the additional elements of: a seal attached to said tubular member opposite said piston; a seat configured in the top of said cylinder for mating engagement with said seat; a cylinder cap over said seat and attached to said cylinder; said cap compressing said seal onto said seat whereby said fluid is sealed internally of said cylinder along said membrane.

7. In a time delay mechanical actuator for switches wherein an accessible' operating member of said switch is thrown by a resiliently powered extending plunger from a mounted dash pot having fluid damping means therein, the improvements comprising: a resilient membrane extending interiorly of said dash pot attached and sealed at one end to the piston of said plunger and at the other end to said dash pot so as to define a boundary of a first fluid reservoir interior of said piston; said piston slideably engaging the walls of said dash pot defining a boundary of a second fluid reservoir; a timer orifice through said piston interconnecting said reservoirs; said membrane urging said piston to a first position in said dash pot and yieldably allowing said piston to be rammed to a second position in said dash pot and there urging said piston to return to said first position at a rate at least proportional to the flow of fluid through said timer orifice.

8. In a time delay mechanical actuator according to claim 7 and wherein: said dash pot includes an adjustable mounting means for selectively positioning said dash pot and said extending plunger away from and into actuat ing engagement with said operating member of said switch.

9. In a time delay mechanical actuator according to claim 7 and wherein: an elongate C-shaped clamp is mounted on said dash. pot; an elongate U-shaped clamp is mounted at either end thereof adjacent a switch for frictional mating engagement of said clamp therein where by said dash pot and plunger may be positioned in and out throwing engagement with said operating member.

References Cited UNITED STATES PATENTS 477,588 6/1892 Barker. 729,014 5/ 1903 Thornton. 3,179,396 4/1965 Bracken.

ARTHUR L. LA POINT, Primary Examiner H. BELTRAN, Assistant Examiner U.S. c1. X.R. 1ss -1, 94, 

